code: def mock_backend():
      mock_backend = mock.MagicMock()
      with mock.patch(
          "mlflow.models.python_api.get_flavor_backend",
          return_value=mock_backend,
      ):
          yield mock_backend
  
file_path: mlflow/tests/models/test_python_api.py
imports: import datetime
  import sys
  from unittest import mock
  import numpy
  import pandas
  import pytest
  import scipy.sparse
  import mlflow
  from mlflow.exceptions import MlflowException
  from mlflow.models.python_api import _CONTENT_TYPE_CSV, _CONTENT_TYPE_JSON, _serialize_input_data
  from mlflow.utils.env_manager import CONDA, VIRTUALENV
label_desc: Use image node_id 3 for calling a global function with example usage: mock_backend() without return types